This invention relates to a novel method of storing processed fish and roe.
Containing much water, fish and roe deteriorate very quickly, so they must be kept fresh until they reach the final outlets of the distribution market. Known methods of fish or roe storage include refrigeration, freezing, drying, salting, etc. But each method has its own defects and is not completely satisfactory. In one method, salted fish is dried whole or open. But salted products are generally stored at a temperature lower than -20.degree. C., so it becomes less tasteful due to protein denaturation or loss of freshness. In addition, they are contacted by air during storage and their quality is easily reduced by oxidation of fat. An attempt was made to prevent putrefaction with an preservative or to prevent lipid denaturation with an antioxidant, but the result was far from being satisfactory and it was impossible to keep salted and dried fish fresh and tasteful over an extended period of time. Addition of chemicals to prevent food deterioration is not a good method in view of food sanitation, and such method is not desirably taken in the future.
Freezing is an effective method to store fish, but once frozen, fish does not return to the original state even when it is thawed, and instead, its tissues decolor and soften, and due to the attack of microorganisms, it is easily deteriorated or putrefied. For instance, eel is frozen for storage after it is grilled without dipping in sauce, but teriyaki having adequate flesh thickness cannot be made of the eel stored by this method, and because of the loss of lipid, the tissues become very loose. This is because fish protein is denatured upon extended storage in a frozen state.
Vacuum packaging is another effective method for storing processed fish, but one of its defects is that air unavoidably enters the pack during storage. Teriyaki of eel is sometimes sold vacuum packed, but for one thing, this method requires expensive equipment and high maintenance cost, and for another, due to creation of vacuum in the pack, the product does not have the flesh thickness required for a good teriyaki. What is more, the quality of the packed product is reduced and the teste of teriyaki served hot is lost.